Cylinder reboring machine



4 SbeesSheet l ATTORNEY Sept 3, 1940. H, PETERSEN CYLINDER REBORING MACHINE Filed March 24, 1958 Sept. 3, 1940. H. PETERsEN 2,213,885

CYLINDER REBORING MACHINE Filed March 24, 1938 4 Sheets-Sheet 2 A TTORNEY Sept. s, 1940. H. PETERSEN 2,213,885

CYLINDER REBORING MACHINE 4 Sheets-Sheet 3 Filed March 24, 1958 ATTORNEY www SePt- 3, 1940- H. PETERSEN 2,213,885

CYLINDER REBORING MACHINE Filed March 24. 1958 l4l Sheets-Sheet 4 ATTORNEY Patented Sept. 3, 1940 UNITED PATE T UFFICI?.

2,218,885 CYLINDER REBORING MAGHINE- Hans Petersen,

Storm Manufacturin Minneapolis, Minh., .assigner to g Company, Inc., Minne- 8 Claims.

This invention has relation to a machine for boring `or reboring the cylinders of internal combustion engines, as, v,for example, the cylinders of automotive vehicle engines.

, 5 A n object of the invention is to provide a machine for boring r reboring the cylinders of internal vcombustion engines which will be of novel and improved construction.

A further object is to provide a machine for ,lp boring or reboring the cylinders of internal combustion engines wherein will be incorporated various improved features and characteristics of construction novel both as individual entities of the machine and in combination with each other.

A further object is to provide a cylinder boring o r reboring machine which will include novel and improved mechanism for accomplishing both the .drive of the cutter or cutting means oi the machine and the feed of said cutter or cuttingv .2,0 means to the Work, or along a cylinder being loored or rebored. l

A fur-ther object iis .to provide a cylinder boring or reboring machine which will include novel and impro-ved mechanism vadapted to be mechanically actuated to the accomplishment of the drive of the cutter ror cutting means of the machine, as Well as to the accomplishment of the feed of said cutter or .cutting means to the Work, or along a cylinder being bored or rebored.

A further object is to provide a machine for I .boring or reboring the cylinders of internal combustion engines which Will be mechanically actuated Vto the `accomplishment of the drive of the cutter or cutting means of the machine, and which Will include novel and improved mechanism lfor .accomplishing the vdrive of said cutter or `cutting means at any desired or predetermined, lnicely ,and accurately controlled and regulated lrate of speed. A further object is to provide a machine for boring or reboring the cylinders of internal come '.bustion engines which will be mechanically actuated to the accomplishment of the feed of the cutter or cutting means to the work, or along a cylinder being bored or rebored, and which will vinclude lnovel and improved mechanism for accomplishing .the feed of said cutter or cutting lmeans at any desired or predetermined, nicely and ,aoeuiately controlled and regulated rate of speed A further object `is to provide a cylinder boring or 4reboring machine Which Will include a cutter or cutting means to be driven and to be fed along a cylinder to Vloe bored or rebored, and Which will 5 `also include novel and improved mechanism for taken on line .5.-5111 Fie. 1.;

accomplishing loo-th .the .drive and the feed oisaid .cutter or .cutting means each .et .any .desired or predetermined, controlled and regulated rate of speed.

And a further object is to provide o cylinder s boring or reborins. -ir 1ac'.l 1i.rie which will include .several novel and ,improved eoristruotionalfeeturcs appartenant to the accomplishment of boring .or schering yoloerations upon the .cylinders of internal Combustion ehehes- With the above 10 objects in View, as -Well es V.others which ,Will eppear as the ,specification proceeds, the invention ccmprises the cqnstnuction, `arrangemrent and combination of parts es to .be fully described as hereinafter to Iloe s eeoioollv claimed, .it Al5 heine understood ...that the .disclosure yherein is merely and .intended `in `no wey in e limiting sense, cheeses in `details ,of construction 1and arrangement of parts .heine permissible s0 .lons .as Within the spirit yof the invention and go.

the scope of the claims V.vv'ljlicli follow.

Inl .the ,accompanying .drawings forming 'e .Part of this specification,

Fie. il is ,o side ,elevational view of a ,cylinder boring or rehorihe mechlrleih which the ieetures l,25 `and characteristics of the invention are incorporatefi, .disclosing `salti machine secured-11.11011 an ,engine hloels in position to commence o rehorine .operation noch va usual cylinder provided in .seid engine block: ,3o

.liie- .2 is er1-end .elevational View of the machine of e .as soie oehine Wol-11d .appear from the righ saisi Fie, 1

Fig. 3 is an enlarged plan view, partially broken away, ,of the `machine as -seen from the top of l35 the sheet 1;

Fig. `i is `an enlarged. horizontal sectional View, taken on 4line `4-.d in Fig. 1;

Fig. 5 is an enlarged, horizontal sectional view,

Fig. 6 is a fragnfient,ary vertical sectional View, '40 taken about as .on line .i6-:6 .in Fig. 3, disclosing a lower portion yof the machine;

Fig. f7 is a fragmentary vertical sectional View, :taken .on line l-7 in Fig. 3, .disclosing an inter- .5,5 mediate portion of the machine;

Fig. 8 is -a fragmentary vertical sectional view, taken on line 3 8 in Fig. 3, disclosing an upper Vportion of the machine; v

Fig. l9 is a fragmentary vertical sectional view, 50 Vtaken on line 9 9 in Fig. 3, disclosing yan intermediate portion of the machine;

Fig. 10 is a fragmentary vertical -sectional View,

taken on line 1Ill- .IIJ in Fig. `3, disclosing .an in- 455 VI5. The length of the driven shaft 23 betweenA 135 the cover or cap member 21,' and the upper l arranged cutter or tool dresser 29 disposed at the taken on line closed in Figs. 1 and 2, during operation of thev machine, in position to operate upon cylinders i1 contained by said block I6. l 1 The frame l5 suitably and conveniently supports an electric motor i8 including a vertically upwardly extending motor shaft I9. The electric motor I8 is bolted, as at 2D, at one of its side porionsto an upright member'2l of the frame l5.

The motor shaft i9 is suitably secured, as at 122, to a vertically upwardly extending shaft 23 adapted to be driven by the electric motor i8. A

lower portion'of the shaft 23 is mounted, as at -24,-in a horizontal bearing member 25 constitut- |5 above the electric motor An ing part of the frame I8 and integral with'the upright member 2| upper portion of said shaft 23 is mounted, as at 26,- in a cover or cap member 21 upon the frame its bearings 24 and 26 is situated in a space 28 between the `horizontal bearing Vmember 25 and end f= 'sai'd shaft 23 xedly carries a, horizontally outer side of and above the cover or cap member 21. -A vertical rod 39 extending upwardly from said cover orl cap member adjacent the cutter or tool dresser may provide a support or holder for a cutter or tool to be dressed.

The frame i 5 integrally includes a hollow, vertical bearing post 3|, and a vertical sleeve 32 is mounted to be reciprocated in said bearing post 3l. Said vertical sleeve 32 may be held against rotary movement in the post 3| in any suitable and convenient manner. A cutter shaft 33 is rotatably mounted, as at 34, within the sleeve 32 and is fixed against longitudinal movement in said sleeve. A lower portion of the cutter shaft 33,-b`elowfsaid sleeve 32, `carries a centering device 35, and the lower end of said cutter shaft, below said centering device, carries a cutter head 36 Ya gear45 detachably :the upper portion with cutter or cutting means.

A gear 31 is fixed upon the vertical driven shaft 23' and is situated in the space 28. Said space 28 also houses a short vertical shaft 38 having its lower end mounted, as at 39, in the frame l5 and its upper portion mounted, as at 45, in the cover or cap member 21. A gear 4| is'fixed to an intermediate portion of the short vertical shaft 32m vthe space 28 and is in mesh with the gear 31.

The upper portion of the-cover or cap member 21'is hollowed out to provide a gear casing 42, and .a cover plate 43 is removably secured, as at 44, to

said gear casing` 42. The gear casing 42 houses or removably secured upon t of theshort vertical shaft 38. A second short vertical shaft 46 is also housed in 4thespace 28 and has its lower end mounted, as `at 41, in the lframe i5 and its upper portion mounted,'as at 43, in said cover or cap member 21. Said gear casing 42 houses a second gear` 43 which meshes with the gear 45 and is detachably or removably secured upon the upper portion of reboring machine inthe short vertical shaft 46. The detachable or removable, intermeshing gears 45 and 49 may be of the same size or of different sizes. They are accessible when the cover plate 43 is removed to be interchangeable for the purpose of varying the rate of speed of drive and feed of the cutter or cutting means of the machine, as will hereinafter be made apparent. That is to say, the construction contemplates the' employment of gears such as 45 and 49 whichA are readily accessible and are interchangeable to the end that any desired and selectively alterable gear ratio can be employed as a part of the operative connection from the electric motor i3 for driving and feeding the cutter or cutting means of the machine, so that the rate of speed of both drive and feed of said cutter or cutting means can be controll'ably varied and regulated. A lower portion of the short shaft 46 xedly carries a gear 50 which is as disclosed situated in the space 28 at location below the gears 31 and 4|.

The gear 56 meshes with a horizontally disposed gear 5l fixed upon a vertical shaft 52. The lower end of the shaft 52 is mounted, as at 53, in

'the frame |5 and an intermediate portion of said Avertical shaft 52 is mounted, as at 54, in the cover vor cap member 21. The vertical shaft 52 extends upwardly a considerable distance above said cover or cap member 21, and theupper portion of said vertical shaft 52 is splined, as at 55.

A tting 56 is rigidly connected tothe upper end portion of the vertical sleeve 32. As disclosed,'the fitting 56 is secured, as at 51, about said vertical sleeve 32 and provides or supplies a chamber 53. The vertical shaft 52 extends upwardly through the chamber 58 and is rotatable and slidable in said tting 56. Said vertical shaft 52 slidably carries a series of drive pulleys 59 fixed by the spline 55 to rotate with the shaft 52. The cutter shaft 33 likewise carries a series of drive pulleys 63 disposed in horizontal alinement with the drive pulleys 59 upon a part of the cutter shaft'extending above the sleeve 32. All of the drive pulleys 59 and 6U are within the chamber 53 of the fitting 56, and drive belts' 6|, one for each of the drive pulleys 59, 5|), ride over the drive pulleys o f the different sets, respectively, to' cause said pulleys 59 to be drivingly connected to said pulleys 6D. It will be apparent'that when the electric motor I8 is driven,

the shaft 52 will be rotated to in turn rotate or drive Vthe cutter shaft 33 through the instrumentality of the drive pulleys 59 and 60 and the drive belts 6|.

Mechanism for causing the vertical sleeve 32,

' and with it the cutter shaft 33, to be reciprocated in the vertical bearing post 3| includesa vertical 'feed screw 62 projecting upwardlyfrom the cover 'which is rotatably mounted andy fixed against longitudinal movement in the machine. As dis- .,closed, the lower end of said vertical shaft 65 is mounted, as at 66, in a` horizontal member of the frame i5, and the upper end of the shaft`65 is mounted, as at 61, 'in the cover or cap member 21,.the bearing 61 being close to the lower end of the vertical Yfeed screw 62.

The fitting 56, with pulleys 59, and the vertical Sleeve 32, with the cutter shaft 33 and the *75 pulleys 68, are caused to be fed up andgdown in the machine, or reciprocated vertically relatively to the frame I5, by rotation of the vertical feed screw 62. Devices are provided whereby said feed screw 52 can lbe driven or rotated by the electric motor I8 at a plurality of different rates of speed, in addition to the different rates for driving or rotating the feed screw 62 which the interchangeable intermeshing gears 45 and 43 are adapted to provide.

Thevertical shaft 52 iixedly supports a worm gear 6.8 which is situated at elevation below the gear 5l adjacent the bearing 53, and said worm gear 88 is in continuous mesh with a vertically disposed worm gear 69 fixed upon a horizontal shaft 10. The horizontal shaft 10 is rotatably supported at its opposite ends, as at 1I, by the frame I5. A shifter shaft 13 has its opposite end portions 14 slidably mounted in and extending beyond portions of the frame l5 at either side thereof, and each end portion 14 iixedly carries a hand piece 15. Said horizontal shaft 19 slidably supports spaced apart gears 15 and 11 constituted as a part of a gear shifter device which also includes spaced apart gears 18 and 19 fixed upon a horizontal shaft 88 having its opposite end portions mounted, as at 8|, in lsaid frame I5. The gears 15 and 11 are fixed to rotate with the shaft 10. The gear 1B is larger lthan the gear 11, and the gear 18 is smaller than the gear 19. By grasping either hand piece 15 and causing the shifter shaft 13 to be slid longitudinally the gears 16, 11 and 18, 19 can by reason of longitudinal movement of the gears 15 and 11 through the instrumentality of the shifter arm 12 in lresponse to movement of said shifter shaft 13be selectively positioned out of mesh as in Fig. 10, or so that the gears 11 and 19 interengage as in Fig. 11, or so that the gears 16 and 18 interengage as in Fig. 12. The gear shifter shaft 13 may be held in any of its intended positions by a spring pressed ball 98 suitably supported by the frame I5 and adapted to selectively lie in spaced apart slots 99 in the shaft 13. In Fig. 10 the gear shifter device is in neutral position, in Fig. 11 said gear shifter device is in condition to accomplish feed of the cutter or cutting means of the machine at relatively slow speed, and in Fig. 12 the gear shifter device is in condition to accomplish feed yof said cutter or cutting means at comparatively faster speed. A coil spring 82 on said shaft 18 and between a wall of the frame l5 and said worm gear 59 is for the purpose of resiliently maintaining said shaft 10 in its proper and ydesired position. The shaft 89 xedly carries a worm gear 83 which meshes with a worm -gear` 84 fixed upon the vertical shaft 65.

It will be evident that upon operation of the electric motor I8 while either of the sets of gears 1S, 18 or 11, 19 is interengaged, the feed screw 62 will be rotated or driven through lthe instrumentality of the operative connections between Asaid electric motor and said feed screw as set forth, and that the speed of rotation of the screw will be greater when the gears 'I6 and 18 are interengaged than when the gears l1 and 19 are interengaged. The electric motor I8 is reversible, and, obviously, rotation of the screw 62 will .cause movement of the fitting 58 along the length of the screw, upwardly or downwardly, depending upon the direction of rotation of said screw.

The machine includes means for manually ro- -tating the feed screw 82 in either direction to accomplish upward or downward reciprocation .of the vertical sleeve 32independent1y of themeltered relatively to chanical drive for said screw. As shown, such means includes a horizontal shaft 85 mounted in and extending beyond opposite walls of the frame l5. The shaft 85 fixedly carries a gear 86 which meshes with the gear 18 fixed upon the shaft 80 carrying the worm gear 83, and a handle 81 upon each end of said shaft 85 is for accomplishing manual rotation of the sha-ft. Each handle 81 is selectively attachable to and detachable from the shaft 85 by a usual clutch mechanism 88. An ordinary purpose of manual feed of the vertical sleeve 32 with cutter orcutting means of the machine is to raise or lower said cutter or cutting means While the cutter shaft 33 isnot being rotated in the operation of positioning the cutter or cutting means relatively to the work. The manual feed may be accomplished while the gear shifter device is in neutral position.

A clamping device 89, disclosed in Figs. 1 and 2, is for the purpose of fastening the machine down upon an engine or cylinder block, such as I6, in proper position for operation upon a cylinder, such as I1, by the cutter or cutting means of the machine, by movement of said cutter or cutting means along the wall of said cylinder. The clamping device 89 may be of any ordinary or preferred construction.

The machine will of course be set upon an engine or cylinder block so that the cutter shaft 33 and the cutter or cutting means are properly cena cylinder to be bored or rebored, before the frame of the machine is clamped or fastened down upon said block. The centering device 35 is for properly centering said cutter shaft 33 and cutter or cutting means and includes a centering head (not shown) at the inner side thereof. The cutter shaft 33v includes an axial passageway 39, and a rod 9i slidably mounted in said axial passageway is for the purpose of manipulating centering elements of said centering device 35. The upper end portion of the rod 9! is associated with a hand ypiece 92 for causing said rod 9i to be slid selectively upwardly or downwardly in the operation of manipulating -said centering elements of the centering device. In practice, the cutter shaft 33 is lowered or depressed to situate the centering device 35 within a cylinder to be bored or rebored, and with said centering device so situated, the rod 9| is manipulated to actuate th'e centering kelements and thus center the cutter or cutting means. During a. boring or reboring operation the centering elements are at their withdrawn position, entirely twithin the centering head of the centering device The machine includes means for automatically stopping the rotation and feed of the cutter shaft 33 at the completion of its downward movement. is denoted 93 and an actuator lever for sai switch 93 is indicated 94. The lever 94 is adapted to be moved to neutral position to cut off power to the electric motor I8 from a source not shown when said cutter shaft completes its downward reciprocation and thus cause said motor to come to rest. An actuator rod 95 is mounted, as at 36, for longitudinally adjustable move- An electric switch for the motor I8 ment upon the vertical sleeve 32, and the lower end 91 of said actuator rod 96 is adapted to engage the lever 94 and throw it to .neutral position of the switch 93k upon downward movel means ofthe machine can each be accomplished at any desired or predetermined, controlled and nicely regulated rate of speed, and by employment of the gear shifter device including the gears 1li,`

1.' In a cylinder boring machine, a frame, a cutter shaft rotatably and'reciprocably carried by said frame, means for causing said ucutter shaft to be rotated, means for causing said cutter shaft to be'reciprocated, an electricmotor for actuating each of said means', and a common operative connection between said motor and each of said means including a'rnotor shaft, a gear fixed upon said motor shaft, a rotatably mounted shaft, a gear fixed upon saidrotatably mounted shaft and meshing with said gear fixed upon said motor shaft, a second rotatably7 mounted shaft, a gear fixed upon said second rotatably mounted shaft and drivingly connected to both of said means, and accessible, interengaging gears fixed upon said rotatably mounted shaft and said second rotatably mounted shaft, respectively, said interengaging gears being adapted to'be interchanged to render said means for causing said cutter shaft to be rotated capable of rotating the cutter shaft at variable rates of speed and to render said means for causing said cuttershaft to bereciprocated capable of reciprocating the cutter shaft at kvariable rates of speed.

2. In a cylinder bormg machine, a frame, a

, cutter shaft rotatably and reciprocably carried by vsaid frame, means for causing said cutter shaft to be rotated, means for causing said cutter shaft to be reciprocated, an electric motor for actuating each of said means, a common operative connection between 'said motor and each of said means including a motor shaft, a gear fixed upon said motor shaft, a rotatably mounted shaft, a gear fixed upon said rotatably mounted shaft and meshing with'said gear fixed upon said motor shaft a second rotatably mounted shaft, a gear fixed upon said second rotatably mounted shaft and drivingly connected to both of said means, and accessible 4interengaging gears fixed upon said rotatably mounted shaft and said second rotatably mounted shaft, respectively, said interengaging gears being adapted to be interchanged to render said means for causing saidcutter shaft t o be rotated capable of rotating the cutter shaft at variable rates of speed and to render said means for causing said cutter shaft to be reciprocated capable of reciprocatingk the cutter shaft at variable rates of speed, and a gear shifter device for making and breaking the driving connection between said gear fixed upon said second rotatably mounted shaft and said means for causing the cutter shaft to be reciprocated and for altering the rate of speed of reciprocation of said cutter shaft. Y

3. In a cylinder boring machine, a frame, a cutter shaft rotatably and reciprocabl'y carried by said frame, means for causing said cutter shaft to bereciprocated, means for causing said cutter shaft to? be rotated, an electric motor for actuat- -ing each of said means, a gear casing upon said frame and opening to an outer side thereof, and

a common operative connectionbetween said motor and each of said means including a motor shaft, a gear fixed upon said motor shaft, a rotatably mounted shaft, a gear fixed upon said rotatably mounted shaft and meshing vwith said gear .fixed upon said motor shaft, a second rotatably mountedshaft, a gear fixed upon said second rotatably mountedishaft, a driving connection between said'gearxed upon said second rotatably mounted shaft Yand both of said means, and accessible, interngaging gears situated in said gear casing and fixed upon said rotatably mounted shaftand said second' rotatably mounted shaft, respectively, A' said interengaging gears being adapted to be interchanged to render said means for causing said cutter shaft'to be reciprocated capable of reciprocating thecutter shaft at variable rates of'speed and'to render said means for causing said cutter shaft to b'e'rotated capable of rotating the cutter shaft at variable rates of speed.

4.' In a cylinder boring machine, a frame, a cutter shaft rotatably and reciprocably carried by said frame, means for causing said cutter shaft to be rotated, means Vforcausing said cutter shaft to be reciprocated, an electric motor for actuating each of said means, a gear casing upon said framev and openingv to an outer side thereof, a common .operative connection between said 'motor and each of vsaid means including a motor shaft, a." gear fixed uponsaid motor shaft, a rotatably mounted shaft, a gear fixed Vupon said rotatably'mounted shaft and meshing with said gear fixed lupon said motor shaft, a second rotatably mounted shaft, a gear xed upon said second rotatably mounted shaft, a ldriving connection between said gear fixed upon said second rtatably mounted shaft and both of said means, and accessible, interengaging gears situated in said gear casing. and fixed upon said rotatably mounted shaft and saidsecond rotatably mounted shaft, respectively, said interengaging gears being adapted vto vbe interchanged to render said means for causing said cutter shaft to be rotated capable of rotatingv the cutter shaft at variable rates of speed and to render said means for` causing said cutter shaft to be reciprocated capablev of reciprocating the cutter shaft at 4variable rates of speed, and a gear shifter device for making and breaking the driving connection between said gear fixed upon; said second rotatably mounted shaft andrv said means` for causing the cutter shaft to be reciprocated and for altering the rate of speed of reciprocation of said cutter shaft.

5. In a cylinder boring machine, a frame, a cutter shaft rotatably and reciprocably carried by said frame', means for causing said cutter shaft to be rotated, means for causing said cutter shaft to be reciprocated, an electric motor for actuating each of said means, a gear casing upon said framel and opening to an outer side thereof, a 'common operative connection between said motor and each of said means including a motor shaft, a gear fixed upon said motor shaft, a rotatably mounted shaft', a gear fixed upon said rotatably .mounted shaft and meshing with said gear iixedupon sa'id'rnotor shaft, a second rotatably mounted shaft, a gear fixed upon said second rotatablyvr mounted shaft, a driving connection betweensaidgear fixed upon said second rotatof speed, and mechanism included as a part of said means for causing said cutter shaft to be reciprocated and constituted as a gear shifter device accessible at the outer side of said frame for altering the rate of speed of recprocation of the cutter shaft, said mechanism being independent of said interengaged, interchangeable gears and of said means for causing said cutter shaft to be rotated.

6. In a cylinder boring machine, a frame, a cutter shaft rotatably and reciprocably carried by said frame, means for causing said cutter shaft to be rotated, means for causing said cutter shaft to be reciprocated, an electric motor for actuating each of said means, a gear casing upon said frame above said electric motor and opening to an outer side of the frame, and a common operative connection between said motor and each of said means including an upright motor shaft, a gear xed upon said motor shaft, an upright rotatably mounted shaft, a gear fixed upon a lower portion of said upright rotatably mounted shaft and meshing with said gear xed upon said motor shaft, a second upright rotatably mounted shaft, a gear iixed upon a lower portion of said second upright rotatably mounted shaft, a driving connection between said gear fixed upon said second upright rotatably mounted shaft and both of said means, and interengaging gears situated in said gear casing and xed upon an upper portion of said upright rotatably mounted shaft and an upper portion of said second upright rotatably mounted shaft, respectively, to be accessible at the outer side of said frame, said interengaging gears being adapted to be interchanged to render said means for causing said cutter shaft to be rotated capable of rotating the cutter shaft at variable rates of speed and to render said means for causing said cutter shaft to be reciprocated capable of reciprocating the cutter shaft at variable rates of speed.

7. In a cylinder boring machine, a frame, a cutter shaft rotatably and reciprocably carried by said frame, means for causing said cutter shaft to be rotated, means for causing said cutter shaft to be reciprocated, an electric motor for actuating each of said means, a gear casing upon said frame above said electric motor and opening to an outer side of the frame, a common operative connection between said motor and each of said means including an upright motor shaft, a gear fixed upon said motor shaft, an upright rotatably mounted shaft, a gear fixed upon a lower portion of said upright rotatably mounted shaft and meshing with said gear fixed upon said motor shaft, a second upright rotatably mounted shaft, a gear fixed upon a lower portion of said second upright rotatably mounted shaft, a driving connection between said gear fixed upon said second upright rotatably mounted shaft and both of said means, and interengaging gears situated in said gear casing and xed upon an upper portion of said upright rotatably mounted shaft and an upper portion of said second upright rotatably mounted shaft, respectively, to be accessible at the outer side of said frame, said interengaging gears being adapted to be interchanged to render said means for causing said cutter shaft to be rotated capable of rotating the cutter shaft at variable rates of speed and to render said means for causing said cutter shaft to be reciprocated capable of reciprocating the cutter shaft at variable rates of speed, and a gear shifter device accessible at the outer side of said frame for making and breaking the driving connection between said gear iixed upon said second upright rotatably mounted shaft and said means for causing the cutter shaft to be reciprocated and for altering the rate of speed of reciprocating of said cutter shaft.

8. In a cylinder boring machine, a frame, a cutter shaft rotatably and reciprocably carried by said frame, means for causing said cutter shaft to be rotated, means for causing said cutter shaft to be reciprocated, an electric motor for actuating each of said means, a gear casing upon said frame above said electric motor and opening to an outer side of the frame, a common operative connection between said motor and each of said means including an upright motor shaft, a gear fixed upon said motor shaft, an upright rotatably mounted shaft, a gear fixed upon a lower portion of said upright rotatably mounted shaft and meshing with said gear fixed upon said motor shaft, a second upright rotatably mounted shaft, a gear fixed upon a lower portion of said second upright rotatably mounted shaft, a driving connection between said gear fixed upon said second upright rotatably mounted shaft and both of said means, and interengaging gears situated in said gear casing and fixed upon an upper portion of said upright rotatably mounted shaft and an upper portion of said second upright rotatably mounted shaft, respectively, to be accessible at the outer side of said frame, said interengaging gears being adapted to be interchanged to render said means for causing said cutter shaft to be rotated capable of rotating the cutter shaft at variable rates of speed and to render said means for causing said cutter shaft to be reciprocated capable of reciprocating the cutter shaft at variable rates of speed, and mechanism included as a part of said 'means for causing said cutter shaft to be reciprocated and constituted as a gear shifter device accessible at the outer side of said frame for altering the rate of speed of reciprocation of the cutter shaft, said mechanism being independent of said common operative connection and the interengaging, interchangeable gears thereof.

HANS PETERSEN. 

